Hot air furnace



D. R. BARD HOT AIR FURNACE Jan. 2, 1934.

Filed May 15, 1933 2 Sheets-Sheet l 3 WU e/wbo b HOT AIR FURNACE Filed May 15, 1935 2 Sheets-Sheet 2 i /5 50 if if 3G Patented Jan. 2, 1934 S'ETES PATENT OFFECE Apphcation May 15, 1

3 iaims.

This invention reiates to furnaces, but more particularly to hot air furnaces utilizing a hydrocarbon burner, and an object is to produce a simple and efficient furnace of this character which is designed to obtain substantially complete combustion and provide an exceptionally large area of radiation surface, thereby reducing the fuel consum tion and making most effective use of the heat generated. jj Another object of the invention is to provide a hot air furnace of such design that the heated gases and products of combustion from the com bustion chamber are caused to roll during their travel and with respect to radiation surfaces in order to radiate the maximum amount of heat and to improve combustion to such extent as virtually to eliminate clogging of the discharge duct.

Other objects and advantages of the invention will hereinafter appear, and, by way of illustra- 51) tion, an embodiment of the invention is shown on the accompanying drawings, in which:

Figure l is a front elevation of the furnace partly in section;

Figure 2 is a sectional View on the line 2-2 o Figure l; and

Figure is a sectional View on the line 33 of Figure l of a radiator assembly showing particularly the manner in which the radiator units or boxes are respectively connected to cause a rolling action or turbulence oi the gases during their travel.

The illustrated embodiment of the invention comprises a hot air furnace having a sheet metal casing 19 provided with a hood 11 from which extend hot air ducts 12. Cold air is introduced to the lower portion or the casing 13 through an inlet 13, through which air is forced by a blower 13 and first contacts a V-shaped baflie 13 which divides the stream of air, directing a portion to 40 each of the radiator assemblies, as will hereinafter appear. Disposed within the casing is a housing 14 providing a combustion chamber 15, and into the lower portion of this housing extends a nozzle 16 of a suitable oil burner.

It will be noted that the casing 10 is spaced from the side and top walls of the combustion chamber except at the front end, andextending from the front wall of the housing 14 is a short pipe 17, on the outer end of which is a hinged gate 18 held closed by its own weight. The gate 18 serves to relieve the pressure on the inside of the combustion chamber in the event of explosion, and thus provides a safety factor.

The products of combustion from the chamber are discharged from the upper portion through 933. Serial No. 671,097

ducts 19 arranged in pairs on opposite sides of the housing 14. Each pair of ducts extends downwardly in substantially parallel relation and connect at their lower ends to a radiator assembly, and since the radiator assembly on each side of the combustion chamber is the same, description of one is deemed sufficient.

The lower ends of the downwardly extending pipes 19 connect to a horizontally elongate box 20 which extends substantially the full depth of the casing is with the ends spaced a short distance from the adjacent walls of the casing. As shown, the box or radiator unit 20 is up Wardly inclined, the lower end thereof being nearer the combustion chamber 15. Disposed above the radiator unit 20 and arranged in parallel relation thereto is a second unit or boxli e structure 21, which is co-extensive with the box 20. The sides of the box 21 are spaced respectively from the casing 10 and combustion chamber 15, and, in this instance the box 21 is of less Width than that of the box 20.

As shown in Figure 3, the pipes 19 are connected to the box 20 intermediate the ends thereof, one pipe being spaced laterally from the other a substantial distance. A pair of pipes 22 connect the units 20 and 21, but these pipes are disposed adjacent the opposite end portions of these boxes or radiator units. Spaced bodily from the box or unit 21 is a third unit 23, which is spaced bodily from the unit 21, but is disposed in parallel relation thereto and is co-extensive with the unit 21. A pair of pipes 24 connect the unit 21 with the unit 23, and, as shown, the pipes 24 are disposed relatively close together in the central portion thereof, thereby causing the heated gases to travel a circuitous route from the box 20, and in so doing impart a rolling action for obtaining maximum heat radiation.

Disposed above the unit 23 in spaced parallel relation and in the region of the upper portion of the combustion chamber 15, is a fourth unit 25, which is substantially rectangular in construction and somewhat larger than the remaining units. The unit 25 is connected to the unit 23 by a pair of pipes 26, one pipe being disposed in the region between the pipes 24, as shown in Figure 3, and the other pipe adjacent one end of the units substantially in alignment with one of the pipes 22. The arrangement of the connecting pipes and ducts is important to compel the heated gases to radiate practically all of the heat through the several units, as will be manifest to those skilled in this art. Leading from the opposite end of the unit 25 is a discharge pipe 27, which also leads from the uppermost unit of the other radiator assembly, and a pipe 28 leads from the pipe 27 for conducting the gases to the outside.

Leading from the outer of each of the radiator units 20, 21, 23 and 25 is a short pipe 29 extending through the wall of the casing 10, and each pipe 29 is closed by a screw cap 30. This enables ready inspection and cleaning of the inside of each unit.

It is manifest that the cold air introduced through the duct 13 passes upwardly on opposite sides of the combustion chamber housing 14. The boxes are all tilted laterally in a shutterlike formation and this insures steady currents of air between successive boxes as well as upwards along their sides, thus obtaining effective heat transference through the bottoms and tops of the boxes as well as through their sides. The lowest box is spaced from the adjacent wall of the casing to allow for the upward passage of air heated by contact with the bottom of the box, and each successively higher box is spaced farther from the adjacent wall of the casing to provide additional room for the upward passage of the air directed outward between the boxes. Obviously, the coldest air first contacts with the hottest radiator, and, in traveling upwardly, successively contacts those radiators which would be relatively cooler.

It has been found by experience that a furnace constructed as herein shown and described works particularly satisfactorily in connection with an oil burner in that more complete combustion is obtained, sooting of the radiators and connecting passages is virtually eliminated, and a much more efficient heating plant is obtained. This, to

a large extent is attributed to the fact that the heated gases from the combustion chamber are not allowed to be directly discharged, and not only are they required to pass through a circuitous path, but owing to the construction and arrangement of the radiators, the gases are required to roll or surge within the radiators, thereby coming into more intimate contact with all portions thereof so that the maximum amount of heat can be radiated.

It is to be understood that numerous changes in details of construction, arrangement and operation may be effected without departing from the spirit of the invention as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A hot air furnace comprising a casing provided with a cold air inlet and a hot air outlet, a combustion chamber and a radiator within the casing, fiues connecting the bottom of the radiator with the combustion chamber, a discharge duct leading from the top of the radiator, the radiator being located between the combustion chamber and a side wall of the casing and. comprising a plurality of superposed radiating boxes connected by ducts, the boxes and ducts forming a circuitous path for products of combustion from the combustion chamber, and the boxes being substantially horizontal longitudinally and all tilted laterally in shutter-like formation with their sides adjacent the side wall of the casing higher than their inner sides.

2. In a hot air furnace, a casing provided with a cold air inlet and a hot air outlet, a combustion chamber located centrally of the casing, a radiator on each side of the combustion chamber between it and a side wall of the casing, ducts leading from the combustion chamber to the bottoms of the radiators, and discharge ducts leading from the tops of the radiators, each radiator comprising a plurality of superposed elongate boxes approximately rectangular in cross section and ducts connecting the boxes and forming with them a circuitous path for the products of combustion, the boxes being substantially horizontal longitudinally and tilted shutter-wise laterally with their higher sides towards the casing wall.

3. A hot air furnace comprising a casing providedv with a cold air inlet and a hot air outlet, a combustion chamber within the casing, a radiator within and adjacent a side Wall of the casing, fiues connecting the combustion chamber with the radiator and a discharge duct leading from the radiator, the radiator comprising a plurality of elongate superposed boxes and ducts connecting the boxes, the boxes and connecting ducts forming a passage for gases from said flues to said discharge duct, the longitudinal axes of each box being approximately horizontal and parallel with the adjacent wall of the casing, all of said boxes being tilted laterally in shutter-like formation with their higher sides towards said adjacent wall and the upper boxes being spaced farther from said adjacent wall than the lower boxes.

DALE R. BARD. 

